1. Field of the Invention:
The present invention relates to a distributor roller for an inking unit of a printing press, and includes a roller axis which is mounted in bearings so as to be fixed against rotation, and a roller casing which is rotatably mounted on the roller axis and is driven such that, via drive means provided within the roller casing, the rotating roller casing is caused to reciprocate axially.
2. Description of the Prior Art:
German Offenlegungsschrift (German Laid Open Patent Application) No. 22 38 481 describes a printing press drive having a distributor roller which can execute rotating and reciprocating movements simultaneously. In this publication, a planetary gear serves as a drive means which, in connection with a cam, causes the roller casing to execute an axial stroke. The described reduction gear yields a maximum gear reduction ratio of 1:4, so that four revolutions of the distributor roller perform a stroke of, for example, 15 mm. However, it has been found that, with highly efficient printing machines, which complete on the order of 40,000 plate cylinder revolutions per hour, such a distributor roller performs on the order of 1,850 revolutions per minute in the inking unit. This results in 460 stroke movements in one minute and 7.5 stroke movements in one second. Such a high-frequency roller motion can cause considerable wear and tear in the drive means and can also generate additional vibration forces which may have detrimental effects on the quality of the printing. In view of the given mass of such a distributor roller, the machine side frame may also be subjected to considerable impact forces.